The present invention relates to a network management system and method and a recording medium on which a network management program is recorded. In particular, the present invention relates to a health check function for detecting any disconnection between a client and a server in a client/server type network management system.
Conventionally, a client/server type system exists as a network management system of this kind, which utilizes Common Object Request Broker Architecture (CORBA). The event service in this system is an implementation of asynchronous event communications between a client and a server.
FIG. 6 illustrates a structure diagram of a client/server type system utilizing CORBA. CORBA is a standard technology by Object Management Group (OMG) which is engaged in the standardization of distributed object technologies. With CORBA, an exchange of methods to and from an object existing somewhere on a distributed object is mediated by an Object Request Broker (ORB) which is one of the components comprising a distributed object environment. In other words, a client 7 does not need to know whether a server 6 is located on the same machine or on a network by virtue of the use of an ORB 5 and is able to transparently invoke a method contained in the server 6.
Besides the ORB 5, another component comprising the distributed object environment is a common object service. Among this service provided by CORBA, asynchronous communications between the client 7 and the server 6 is implemented by an event service. In the event service, a sender of events is referred to as "supplier" and a receiver of events is referred to as "consumer." The asynchronous communications are implemented by the use of an object called "event channel." The event channel allows a plurality of suppliers to communicate with a plurality of consumers asynchronously and without any knowledge of each other.
There are provided two ways of event communications using the event channel, namely, the push style and the pull style. FIGS. 7 and 8 illustrate these event communication methods, respectively.
For the push style as shown in FIG. 7, a supplier 8 is to have an initiative and transmit events to consumers 10-1 and 10-2. Specifically, the supplier 8 will first be requesting while an event channel 9 requested so that data may be transmitted from the supplier 8 to the event channel 9. The event channel 9 will then be requesting and the consumers 10-1 and 10-2 requested, so that the event channel may transmit the data to the consumers 10-1 and 10-2.
For the pull style as shown in FIG. 8 on the other hand, a consumer 10-1 is to have an initiative and request events from a supplier 8. Specifically, the consumer 10-1 will initially be requesting while an event channel 9 requested so that the consumer 10-1 may request data to be transmitted from the event channel 9. The event channel 9 will then be requesting and the supplier 8 requested, so that the event channel 9 may request the data to be transmitted from the supplier 8.
The client/server type system utilizing CORBA as described above is discussed in detail by Hirofumi Onodera in "CORBA: A Distributed Object Oriented Technology," published by Soft Research Center, Apr. 25, 1996, pp. 182 to 185.
For the client/server system utilizing conventional CORBA as described above, there are two methods for event communications using the event channel, namely, the push style and the pull style. In this case, for the pull style, a client is requesting from the event channel and is therefore able to detect any errors. For the push style, however, the client will be requested by the event channel and is therefore unable to detect errors such as disconnection.
Consequently, in the pull style event service, the client that is a consumer can detect errors such as disconnection while in the push style, the client can not detect such errors.